WASHINGTON—According to a study released Thursday by the Center for Applied Linguistics, nearly two-thirds of all human speech transpires under people’s breath. “Our data indicates that, whether in the form of hushed grumbles of anger, a half-delivered retort, or quiet self-berating, the majority of all spoken language is delivered in barely audible mutters,” said researcher Erin Wightman, adding that a sizable quantity of all human vocalizations are imperceptible insults made while walking away from an argument, a meeting with one’s supervisor, or a pleasant conversation with someone that the speaker simply does not care for. “We found that many people will whisper to themselves at night about mistakes made earlier in the day, while others will pepper in low-volume sarcastic comments while interacting with coworkers or family members. The sheer number of words that are spoken for no one else’s benefit is astounding.” Wightman then went on to make a muffled, half-intelligible comment about both her fellow researchers and the gathered members of the press.